func draw_selections(viewp, bufferp, crp unsafe.Pointer, mark_pairs []unsafe.Pointer) {
view := (*C.GtkTextView)(viewp)
buffer := (*C.GtkTextBuffer)(bufferp)
cr := (*C.cairo_t)(crp)
var alloc C.GtkAllocation
C.gtk_widget_get_allocation((*C.GtkWidget)(viewp), &alloc)
n := len(mark_pairs)
var start_mark, stop_mark *C.GtkTextMark
var location C.GdkRectangle
var iter C.GtkTextIter
var x, y C.gint
var dx, dy C.double
for i := 0; i < n; i += 2 {
start_mark = (*C.GtkTextMark)(mark_pairs[i])
C.gtk_text_buffer_get_iter_at_mark(buffer, &iter, start_mark)
C.gtk_text_view_get_iter_location(view, &iter, &location)
C.gtk_text_view_buffer_to_window_coords(view, C.GTK_TEXT_WINDOW_WIDGET, C.gint(location.x), C.gint(location.y), &x, &y)
if C.int(x) > alloc.width || C.int(y) > alloc.height || x < 0 || y < 0 {
continue
}
dx = C.double(x)
dy = C.double(y)
C.cairo_set_source_rgb(cr, 1, 0, 0)
C.cairo_move_to(cr, dx, dy)
C.cairo_set_line_width(cr, 2)
C.cairo_line_to(cr, dx+6, dy)
C.cairo_stroke(cr)
C.cairo_move_to(cr, dx, dy)
C.cairo_set_line_width(cr, 1)
C.cairo_line_to(cr, dx, dy+C.double(location.height))
C.cairo_stroke(cr)
stop_mark = (*C.GtkTextMark)(mark_pairs[i+1])
C.gtk_text_buffer_get_iter_at_mark(buffer, &iter, stop_mark)
C.gtk_text_view_get_iter_location(view, &iter, &location)
C.gtk_text_view_buffer_to_window_coords(view, C.GTK_TEXT_WINDOW_WIDGET, C.gint(location.x), C.gint(location.y), &x, &y)
if C.int(x) > alloc.width || C.int(y) > alloc.height || x < 0 || y < 0 {
continue
}
dx = C.double(x)
dy = C.double(y)
C.cairo_set_source_rgb(cr, 0, 1, 0)
C.cairo_move_to(cr, dx, dy)
C.cairo_set_line_width(cr, 1)
C.cairo_line_to(cr, dx, dy+C.double(location.height))
C.cairo_stroke(cr)
C.cairo_move_to(cr, dx, dy+C.double(location.height))
C.cairo_set_line_width(cr, 2)
C.cairo_line_to(cr, dx-6, dy+C.double(location.height))
C.cairo_stroke(cr)
}
}
// Draw given poligon path, automatically closing first and last point
func (i *Image) DrawPoly(points ...float64) {
C.cairo_move_to(i.Ctx, C.double(points[0]), C.double(points[1]))
for j := 2; j < len(points); j += 2 {
C.cairo_line_to(i.Ctx, C.double(points[j]), C.double(points[j+1]))
}
C.cairo_close_path(i.Ctx)
}
func (self *Surface) LineTo(x, y float64) {
C.cairo_line_to(self.context, C.double(x), C.double(y))
}
// LineTo is a wrapper around cairo_line_to().
func (v *Context) LineTo(x, y float64) {
C.cairo_line_to(v.native(), C.double(x), C.double(y))
}
//LineTo adds a line to the path from the current point to p in user space
//coordinates.
//
//If there is no current point, LineTo will behave as if preceded by a call
//to MoveTo(p)
//
//Originally cairo_line_to.
func (c *Context) LineTo(p Point) *Context {
x, y := p.c()
C.cairo_line_to(c.c, x, y)
return c
}